An adhesive composition is disclosed which includes a polymer prepared by copolymerizing a monomer containing a polymerizable group, the polymer including a low-molecular-weight component having a molecular weight equivalent to 1% or less of the weight-average molecular weight of the polymer, the low-molecular-weight component is contained in a range of not less than 0 weight % to less than 0.3 weight % of the total weight of the polymer. This allows provision of an adhesive composition having great adhesive strength in a high-temperature environment, especially at temperatures from 140° C. to 200° C., as well as high heat resistance and favorable crack resistance.